Method and apparatus for producing insulating material



s. PALMER 2,958,919

METHOD AND APPARATUS FOR PRODUCING INSULATING MATERIAL Nov. 8, 1960Filed Feb. 12, 1959 2,958,919 Q6 Patented Nov. 8, 1960 NLETHOD ANDAPPARATUS FOR PRODUCING INSULATING MATERIAL Stanley Palmer, Brighouse,England, assignor to Versil Limited, Liversedge, England, a Britishcompany Filed Feb. 12, 1959, Ser. No. 792,812 Claims priority,application Great Britain May 14, 1958 3 Claims. (Cl. 28-1) Thisinvention is particularly concerned with improvements in the productionof webs or mats formed or composed of extrudable filamentary material,such as glass fibre, and applicable primarily for the purpose of thermalinsulation in industrial buildings, plant, aircraft, refrigerators andthe like.

Various methods have before been proposed for forming webs or mats fromfilamentary material by applying strands composed of groupedmonofilaments on to a belt conveyor either in continuous or shortso-called staple lengths in such manner as to build up a web or mat ofthe required thickness, a suitable binder being applied to retain theform of the Web or mat. Webs or mats produced by the known methodsreferred to are particularly suitable for the manufacture of reinforcedglass fibre laminates.

The present invention, however, is concerned with producing webs or matssuitable for thermal insulation, and for this purpose it is desirablethat the web or mat should have'the highest possible degree of porosityor still air content.

The present invention has for its object to provide an improved methodand apparatus for the production of webs or mats from extrudablefilamentary material whereby the filamentary material may be deliveredon to a conveyor in the form of short curled lengths or portions to forma web or mat having a high thermal insulating capacity.

According to the present invention, a method for the production of a webor mat for thermal insulation purposes comprises causing a strandcomposed of grouped monofilaments to execute a sharp change in directionwhereby the strand is caused to assume a curled formation, separatingthe curled formation into short lengths and delivering the curled shortlengths on to conveyor means in such manner as to build up a web or mathaving a high degree of porosity.

More specifically, the invention includes a method for the production ofa Web or mat for thermal insulation purposes, which comprisesattenuating and grouping to. gether a number of continuously extrudedfilaments to form a strand, drawing the strand so formed over or throughmeans adapted to induce differential tensional stresses in theindividual monofilaments of the strand so that the strand is caused toassume a curled formation, separating the curled formation into shortlengths and delivering the curled short lengths of strand on to conveyormeans in such manner as to build up a web or mat.

The invention includes apparatus for carrying out the method abovedefined, comprising means for attenuating and grouping together a numberof continuously formed monofilaments to form a continuous strand, an airtraction device arranged to draw the strand so formed over or throughmeans causing the strand to execute a sharp change in direction wherebydifferential stressing of the individual monofilaments results in acurled formation of the strand fed into an outlet pipe delivering on toconveyor means, the arrangement being such that intermittent obstructionof air flow through the outlet pipe by tne curled fibres and consequentpressure built up behind the curled fibres successively severs curledportions from the continuous strand for discharge through the outletpipe on to the conveyor means. A sharp change of direction of the strandmay be obtained by drawing the strand over a knife edge or the likearranged adjacent the inlet to the, air traction device by which thecurled portions are separated from the strand and delivered on to theconveyor means. Grouping of the individual monofilaments may be efiectedin known manner by the use ofa V-grooved drum on which the groupedfilaments are tensioned by means of an air traction device whichdelivers the continuous strand to the curling, severing and deliveringmeans constituted by the air traction device first referred to.

According to a further feature of the invention, the conveyor meanscomprises upper and lower endless conveyors spaced apart according tothe desired thickness of the web or mat to be built up. Means areprovided for spraying the curled portions separated from the strand witha suitable binder and for drying or curing the binder as the web or matis carried by the conveyor means to a discharge point. The spacingbetween the upper and lower endless conveyors may be adjustable toregulate the thicknessof the finished web or mat. Moreover, the rate offeed of the endless conveyors may be controllable to regulate thedensity of the web or mat.

The invention includes webs or mats produced by the method and/orapparatus herein defined.

The invention is hereinafter described, by way of ex-' ample, withreference to the accompanying drawings in which: I

Fig. 1 is a diagrammatic view showing apparatus constructed and arrangedfor carrying out the method according to the invention;

Fig. 2 is aside elevation of part of the apparatus shown in Fig. 1; and

Fig. 3 is an end elevation of the apparatus shown in Fig. 2.

In carrying the invention into effect according to one embodiment,continuous monofilaments 1 of glass extruded from a furnace 2 arecollected by means of a hopper 3 and led into a V-groove 4 in theperiphery of a drum 5 whereby the monofilaments 1 are grouped together.An air traction device 6 is arranged to withdraw the continuous strand 7composed of the grouped monofilaments 1 from the drum 5 and to exertsufiicient tension for attentuating the monofilaments 1 in their passagefrom the furnace 2 to the drum 5. The air traction device 6 delivers thestrand 7 through a pipe 8.

From the outlet of the pipe 8 the continuous strand 7 is drawn by theaction of an air traction device 9 over a knife edge 10 arrangedadjacent the inlet to the air traction device 9 so that the strand 7 iscaused to execute a sharp change in direction whereby the individualmonofilaments are differentially stressed so that the strand passinginto an inlet portion of an outlet pipe 12 assumes a curled formation.As shown in Fig. 2, the air traction device 9 consists of a generallycylindrical sleeve body 30 having a transverse wall 31 at one endthereof, said wall having an inlet opening therein. A tubular extension32 surrounds the opening and extends longitudinally within the sleevebody beyond the lateral opening in the sleeve body through whichpressure air is introduced from the compressor 14. At its other end thesleeve body 30 converges into the outlet restriction 13. By reason ofthe constriction 13 which merges into the outlet pipe 12, the curledstrand is caused to build up so as momentarily to obstruct the air flowthrough the pipe 12. When the air pressure builds up behind the curledfibres to a suitable extent, the portion of curled fibres within theinlet portion 11 of the pipe 12 is forcibly expelled through the pipe 12and thereby servered from the continuous strand 7. Air under pressurefor the operation of the air traction devices 6 and 9 is delivered froma suitable compressor 14 driven by an electric or other motor 15.

The curled portions of fibre are discharged from the outlet pipe 12, asindicated at 7a, to conveyor means, e.g. between upper and lower endlessconveyors, such as belts 16, 17 of open-mesh material, the curled fibreportions 7a being sprayed with a suitable binder, e.g. from a nozzle 18.The binder is dried or cured as by applying hot air through distributorheads 19 communicating with branch ducts 20 from a hot air supplyconduit 21.

At least a delivery portion 12a of the outlet pipe 12 may be laterallyoscillatable for distributing the curled fibre portions 7a on to theconveyor 17. If desired, moreover, two or more units may be arrangedside by side in coniun otion with a single conveyor means.

Preferably the distance between the conveyor belts 16 and 17 isadjustable for controlling the thickness of the eventual web or that 22.The density of the Web or mat may be controlled by regulating the speedof travel of the conveyor belts 16, 17. Any density between 0.5 and lbs.per cubic foot can be readily obtained. The type and amount of binderused may be regulated to vary the degree of rigidity of the productwhich may range from a very flexible mat to a rigid board.

It will be understood that the invention is not limited to theparticular embodiments hereinbefore described. For example. instead of aknife edge, any other suitable means may be provided for causing thestrand to execute a sharp change in direction for the purpose referredto. Alternatively, any other suitable means may be employed for causingthe strand to assume a curled or helical formation and for severingcurled portions and delivering them onto conveyor means so as to buildup a web or mat.

I claim:

1. Apparatus for forming certain individual monofilaments of acontinuously running linear strand of said monofilaments into curledconfigurations and for successively separating from the continuousstrand short lengths of strand containing said curled monofilaments,comprising an air traction device including a generally cylindricalsleeve body having a transverse wall at one end thereof, said wallhaving an opening therein and a tubular extension surrounding saidopening and extending inwardly longitudinally within said sleeve for aportion of the length thereof, said sleeve body having a lateral openingin the wall portion thereof intermediate said sleeve body end Wall andthe free extremity of said tubular extension, the wall of said sleevebody converging at its other end into an outlet constriction, and meansfor passing fluid under pressure through said sleeve body lateralopening, through said sleeve body, and out through said outletconstriction; a deformation element positioned adjacent the inletopening of said sleeve body; and means continuously feeding the strandof grouped monofilaments first angularly across said deformation elementfor frictional engagement thereby to cause differential stressing ofindividual monofilaments of the strand resulting in curled deformationthereof and then into said inlet opening and through said tubularextension, the sleeve body outlet constriction causing intermittentbuilding up of the curled monofilaments to momentarily obstruct thepressure fluid flow through the outlet constriction so that the fluidpressure behind the portion of builtup curled monofilaments willforcibly expel the same through the outlet constriction andsimultaneously sever the built-up portion from the following continuousstrand.

2. The method of successively severing a continuously running linearstrand of monofilaments into short lengths of curled monofilament groupswhich comprises the steps of drawing the strand across monofilamentstressing means to induce differential stresses in the individualmonofilaments to form the same into generally curled configurations,causing said curled monofilaments to build up into a group, and applyinga fiuid force longitudinally to said built-up group of curledmonofilaments to sever the same from said strand.

3. Apparatus as defined in claim 1 wherein said deformation element is aknife edge.

References Cited in the file of this patent UNITED STATES PATENTS2,230,272 Slayter Feb. 4, 1941 2,313,630 Dockerty Mar. 9, 1943 2,379,824Mummery July 3, 1945 2,723,215 Biefeld et al. Nov. 8, 1955 2,736,676Frickert Feb. 28, 1956 2,859,506 Slayter Nov. 11, 1958 2,869,967 BreenJan. 20, 1959 2,938,256 Bauer et a1 May 31, 1960 FOREIGN PATENTS 558,297Great Britain Dec. 30, 1943 722,756 Great Britain Ian. 26, 1955

